Morphology of Flowering Plants
Tap Root System:-
In majority of the dicotyledonous plants, the direct
elongation of the radicle leads to the formation of primary root which grows
inside the soil. It bears lateral roots of several orders that are referred to
as secondary, tertiary, etc. roots. The primary roots and its branches
constitute the tap root system, as seen in the mustard plant.
Fibrous Root System:-
In monocotyledonous plants, the primary root is
short lived and is replaced by a large number of roots. These roots originate
from the base of the stem and constitute the fibrous root system, as seen in the
In some plants, like grass, Monstera and the banyan
tree, roots arise from parts of the plant other than the radicle and are called
Functions of Roots:
The main functions of the root system are absorption
of water and minerals from the soil, providing a proper anchorage to the plant
parts, storing reserve food material and synthesis of plant growth regulators.
Regions of the Root
The root is covered at the apex by a thimble-like structure called the root cap.
It protects the tender apex of the root as it makes its way through the soil. A
few millimetres above the root cap is the region of meristematic activity. The
cells of this region are very small, thin-walled and with dense protoplasm. They
divide repeatedly. The cells proximal to this region undergo rapid elongation
and enlargement and are responsible for the growth of the root in length. This
region is called the region of elongation. The cells of the elongation zone
gradually differentiate and mature. Hence, this zone, proximal to region of
elongation, is called the region of maturation. From this region some of the
epidermal cells form very fine and delicate, thread-like structures called root
hairs. These root hairs absorb water and minerals from the soil.
Modifications of Root
Roots in some plants change their shape and structure and become modified to
perform functions other than absorption and conduction of water and minerals.
They are modified for support storage of food and respiration.
Modification for Food Storage:
Tap roots of carrot, turnips and
adventitious roots of sweet potato, get swollen and store food.
Modification for Support: Banyan trees, after growing to a large size,
develop hanging roots from branches. These are called prop roots. Similarly, the
stems of maize and sugarcane have supporting roots coming out of the lower nodes
of the stem. These are called stilt roots.
Modification for Respiration:
In some plants such as Rhizophora growing
in swampy areas, many roots come out of the ground and grow vertically upwards.
Such roots, called pneumatophores, help to get oxygen for respiration.
Morphology in Flowering Plants: The Stem and The Leaf
Morphology in Flowering Plants: The Inflorescence and Flower
Morphology in Flowering Plants: The Fruit and The Seed
Morphology in Flowering Plants: Important Families and Floral Formula
Morphology in Flowering Plants: NCERT Solution